This disclosure relates generally to wellbore cementing operations. In particular, this disclosure relates to methods for more effectively drawing cement up an annulus toward the surface during wellbore cementing operations.
In drilling a borehole (or wellbore) into the earth for the recovery of hydrocarbons from a subsurface formation, it is conventional practice to connect a drill bit to the lower end of a tubular conduit (e.g., drill string, coiled tubing, etc.). The drill bit is then rotated either alone or along with the tubular conduit as weight-on-bit (WOB) is applied to engage the formation and drill the borehole along a predetermined path. As the borehole extends deeper within the subterranean formation, casing is inserted into the borehole to line the borehole, to provide additional structural reinforcement for borehole (i.e., to prevent collapse of the borehole wall), to prevent undesired outflow of drilling fluid into the formation or inflow of fluid from the formation into the borehole, and to prevent cross-flow between different formations via the borehole.
To secure the casing in position within the borehole, cement is pumped down the casing, and allowed to flow back up the annulus between the casing and the borehole sidewall. The cement is then allowed to set and cure, thereby securing the casing in position within the borehole.